It is for this reason that the most valuable diamonds are colorless. The absence of color allows the most natural light to pass through the diamond. Color is "graded" on a scale, from colorless to light yellow. Although the majority of diamonds appear to be colorless, virtually all have a tint of body color. If all other factors are equal, as the amount of color increases, the price of a diamond decreases (though this does not necessarily reduce the beauty of a diamond).